title: Three-dimensional model for human anterior corneal surface.
abstract: The anterior corneal asphericity (Q) with the tangential radius is calculated, and a three-dimensional (3-D) anterior corneal model is constructed. Tangential power maps from Orbscan II are acquired for 66 young adult subjects. The Q-value of each semimeridian in the near-horizontal region is calculated with the tangential radius. Polynomial fitting is used to model the 360-semimeridional variation of Q-values, and to fit the Q-values in the near-vertical region. Furthermore, a customized 3-D anterior corneal model is constructed. The 360-semimeridional variation of Q-values is well fitted with a seventh-degree polynomial function for all subjects. The goodness of fit of the polynomial function was >0.9, and the median value was 0.94. The Q-value distribution of the anterior corneal surface showed bimodal variation. Additionally, the Q-values gradually become less negative from the horizontal to the vertical semimeridians in the four quadrants. The 3-D surface plot of the anterior corneal surface approximated a prolate ellipsoid. Using a method to calculate the Q-value with the tangential radius combined with polynomial fitting, we are able to obtain the Q-value of any semimeridian. Compared with general models, this method generates a complete shape of the anterior corneal surface using asphericity.
authors.affiliation: The Second Affiliated Hospital of Wenzhou Medical College, Department of Ophthalmology, Wenzhou 325027, China.
authors.forename: Suilian
authors.initials: S
authors.lastname: Zheng
authors.forename: Jinglu
authors.initials: J
authors.lastname: Ying
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Zhonghao
authors.initials: Z
authors.lastname: Xie
authors.forename: Xueping
authors.initials: X
authors.lastname: Huang
authors.forename: Mingguang
authors.initials: M
authors.lastname: Shi
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D003315:Cornea / Q000033:anatomy & histology / Q000473:pathology*; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D020731:Keratomileusis, Laser In Situ; D016014:Linear Models; D008297:Male; D008962:Models, Theoretical; D012044:Regression Analysis; D055815:Young Adult